This proposal will utilize innovative, technologies to allow below the knee amputees to walk and run using a single powered prosthetic device. Current users of passive prosthetic devices typically expend more energy;have reduced ankle motion and power;and increased gait asymmetry resulting in joint and back pain. Augmenting ankle power with a robotic tendon actuator will restore near able bodied function improving quality of life. A pilot study will be conducted in preparation for a larger biomechanics study in phase two. A new running controller will be developed based on the motion of the shank. This funding opportunity will be used for production and development costs, and testing the bionic ankle on two participants. A commercially available walk/run bionic ankle could be developed in 2.5 years with the support of this grant. PUBLIC HEALTH RELEVANCE: This research project develops a powered walk/run prosthetic ankle to restore able-bodied function to a below the knee amputee. Within the U.S. there are approximately 1.2 million people living with a lower limb amputation with 100,000 new cases each year.